The goals of Core C (Biostatistics and Data Management) are to provide expert biostatistical guidance in the design, conduct and analysis of research projects comprising the P01, and to provide a reliable and accurate data management system for projects involving clinical data. The aims of Core C are to provide biostatistical support to P01 projects at every stage of the research: Prior to the initiation of studies, Core staff will consult with investigators to help them select efficient designs and sample sizes that will give adequate power to address study objectives. For clinical studies, they will work with investigators to help set up effective patient recruitment strategies and design case report forms that collect all required information in an unambiguous way. As studies proceed, Core staff will assist in reviewing project databases and monitoring the quantity and quality of data collected, and will suggest modifications to the design or analysis plan as appropriate. When studies are finished, the Core will conduct correct and efficient data analyses, prepare any necessary graphs and tables, assist investigators with the preparation of presentations and manuscripts, and consult on the design of subsequent research. The work of Core C will interface with that of the Physics core providing data management activities during clinical projects, and with the Animal core as laboratory studies are planned and executed. The Core C staff members have extensive experience supporting cancer research, with strong backgrounds in basic science, translational research and clinical trials in addition to being themselves researchers in statistical methods. With their many years of experience with the PDT group, they look forward to further collaborative opportunities for both applying existing methods and adapting or developing new methods as needed.